Are Calcium Supplements Safe?

Kidney stones are a known risk, but studies have investigated other potential safety concerns, including an increased risk of death, cancer and heart disease.

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By Richard Klasco, M.D.

Oct. 12, 2018

Q. Are calcium supplements safe?

A. The short answer is probably yes.

Many people, especially women, take calcium supplements in the hope of building stronger bones, but whether calcium supplements prevent fractures remains uncertain. The United States Preventive Services Task Force advises postmenopausal women against taking 1,000 milligrams a day or less for preventing fractures and says not enough is known about the risks and benefits of taking higher doses.

Calcium supplements probably do not increase the risk of heart disease. The best evidence, again, comes from the Women’s Health Initiative study of calcium and vitamin D. A Harvard review supports this conclusion, stating that “calcium intake, either from diet or from supplements, has little or no effect on cardiovascular disease risk.”

Because Preventive Services Task Force guidelines stop short of recommending calcium supplements, the decision on whether to take them must depend on your individual health concerns. A history of osteoporosis, for example, might argue in favor of calcium supplements, whereas a history of kidney stones might be a reason to avoid them. Calcium can also interact with certain medications, such as the thyroid medicine levothyroxine or the popular anti-osteoporosis drug Fosamax.

Aside from these concerns, there is ample evidence to suggest that calcium supplements are safe.